2026 NPPES data Internal Medicine Physician NPI 1184617979 MD
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Fernando Raul De Castro, MD

Internal Medicine Physician in Phoenix, Arizona. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 172,858 in Internal Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.

Federal data, no proprietary rating. We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
6K
Medicare Part D claims · 405 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
79%
generic claims · 18% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Fernando Raul De Castro, MD filed 6,160 Medicare Part D claims in 2023 as a Internal Medicine Physician in Phoenix, Arizona, prescribing 79% generic.

6K
Part D claims, 2023
79%
generic prescribing

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.

Fernando Raul De Castro, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023, across all CMS prescribers nationally

6,160 Top 5% higher than 95% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2K+: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

Board-eligible specialty (heuristic, not verified)

Fernando Raul De Castro, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Fernando Raul De Castro, MD?

Quality data not reported

NPI registry status

Active

Issued 08/26/2005

NPI 1184617979

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

6,160 127% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Arizona

How Internal Medicine Physician compares to other specialties among Arizona providers

Arizona providers
Pharmacist - 5.6%Pharmacist5.6%Behavior Technician - 5.6%Behavior Technician5.6%Family Nurse Practitioner - 4.3%Family Nurse Practitioner4.3%Physical Therapist - 4.2%Physical Therapist4.2%Speech-Language Pathologist - 3.5%Speech-Language Pathologist3.5%Student in an Organized Health Care Education/Training Program - 3.5%Student in an Organized Health Care Education/Training Program3.5%Internal Medicine Physician - 2.7%Internal Medicine Physician2.7%
Largest specialties in Arizona (% of in-state providers)

Board certification

Not published by CMS

CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Internal Medicine Physician. Verify directly:

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

Fernando Raul De Castro, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 4150 N 108TH AVE, Phoenix, AZ, 85037, with a listed phone of (623) 322-1145. NPI 1184617979 was issued on 08/26/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what De Castro most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 6,160 prescription claims written by this provider, covering 405 Medicare beneficiaries and totaling roughly $1.0 million in drug spend, split 18% brand-name and 79% generic by claim count, with an opioid prescribing rate of 0.3%. These figures capture only Medicare Part D, commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

4150 N 108TH AVE
Phoenix, AZ 85037

Provider Details

NPI 1184617979
Specialty Internal Medicine Physician
Credentials MD
Gender Male
NPI Issued 08/26/2005

Brand vs generic prescribing mix · Typical

Fernando Raul De Castro, MD - brand share 18.0%
Internal Medicine Physician average

18% brand-name claims vs 79% generic, on 6,160 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

6,160
Total Claims
$1.0M
Total Drug Cost
405
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
13,943
Total Day Supply
411,506
Brand vs Generic
18% brand / 79% generic
Brand Drug Cost
$938K
Generic Drug Cost
$101K
Opioid Claims
21 (0.3% rate)
Antibiotic Claims
72

Patient Demographics

Average Patient Age
73.6 years
Avg HCC Risk Score
1.21
Gender Split
55% female / 45% male
Age Distribution
<65: 29, 65-74: 190, 75-84: 154, 85+: 32

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Fernando Raul De Castro, MD prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
512
Lisinopril
364
Metformin Hcl
318
Amlodipine Besylate
261
Pravastatin Sodium
207
Levothyroxine Sodium
202
Losartan Potassium
181
Simvastatin
140
Hydrochlorothiazide
138
Gabapentin
126

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Internal Medicine Physician Overview

How Fernando Raul De Castro, MD fits within the Internal Medicine Physician landscape nationally.

172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider

Fernando Raul De Castro, MD's 6,160 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Arizona

Other clinicians with the same primary specialty enrolled in Arizona, drawn from the same CMS NPPES roster as De Castro.

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Before you book an appointment

Use this federal record as your verification checklist, not as a recommendation.

  • Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
  • Check the active license and any disciplinary history with the Arizona medical board, federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Internal Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers

Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.

Frequently Asked Questions

What is Fernando Raul De Castro, MD's specialty?
Fernando Raul De Castro, MD specializes in Internal Medicine Physician and practices in Phoenix, Arizona. Credentials: MD.
How much does Fernando Raul De Castro, MD prescribe under Medicare Part D?
In 2023, Fernando Raul De Castro, MD wrote 6,160 Medicare Part D claims totaling $1.0M in drug costs for 405 beneficiaries.
Where is Fernando Raul De Castro, MD located?
Fernando Raul De Castro, MD is located at 4150 N 108TH AVE, Phoenix, AZ, 85037. Phone: (623) 322-1145.
What is Fernando Raul De Castro, MD's NPI number?
Fernando Raul De Castro, MD's National Provider Identifier (NPI) is 1184617979, issued on 08/26/2005.
Does Fernando Raul De Castro, MD prescribe more brand-name or generic drugs?
Fernando Raul De Castro, MD's prescribing is 18% brand-name and 79% generic drugs by claim count, with $938K in brand drug costs.
Does Fernando Raul De Castro, MD prescribe opioids?
Yes, Fernando Raul De Castro, MD had 21 opioid claims in 2023 with an opioid prescribing rate of 0.3%.
How many Internal Medicine Physician providers are there in the US?
There are 172,858 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Fernando Raul De Castro, MD prescribe most often?
Based on 2023 Medicare Part D data, Fernando Raul De Castro, MD's most frequently prescribed drugs include Atorvastatin Calcium, Lisinopril, Metformin Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Fernando Raul De Castro, MD accept Medicare?
Fernando Raul De Castro, MD appears in CMS Medicare data with 6,160 Part D claims and 405 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Fernando Raul De Castro, MD's credentials?
Fernando Raul De Castro, MD's NPI is 1184617979 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology

Compiled from official public sources by the PlainDoctor editorial team.